A user of a head-mounted display unit connected to a game machine would wear the head-mounted display unit on the head and operate a controller or the like to play a game while watching a screen image displayed on the head-mounted display unit. In an ordinary display unit of the installation type connected to a game machine, the visual field range of the user spreads also to the outside of the screen image of the display unit. Therefore, the user cannot sometimes concentrate its attention to the screen image of the display unit or sometimes lacks in sense of immersion in the game. In this regard, if the head-mounted display unit is worn, then the user does not look at any other than the image displayed on the head-mounted display unit. Therefore, there is an effect that the sense of immersion in the video world is enhanced and the entertainment property of the game is enhanced further.
Further, if the head-mounted display unit is configured such that, when a panorama image is displayed on the head-mounted display unit and the user who wears the head-mounted display unit turns its head, a panorama image or a virtual space over 360 degrees is displayed on the head-mounted display unit, then the sense of immersion in the video is further enhanced and also the operability of an application such as a game is improved.